1. Field of the Invention
The present invention relates to communication services, and more particularly, to a method and a device for supporting a call service according to network identification numbers.
2. Description of the Related Art
With the rapid development of technology, a mobile communication terminal, which is initially designed to provide simple voice communication and short message transmission functions, has developed to provide diverse functions such as video communication, electronic pocketbook, and Internet functions. Mobile communication terminals have also come to provide a digital camera function, both still image capture and moving image (video) capture.
A mobile communication terminal user, in order to use a mobile communication service, i.e. a call service, typically subscribes to a specified service provider, and performs calling within the coverage range of a base station provided by the corresponding service provider. In this case, the mobile communication terminal must be assigned with an identifier, i.e. a subscriber information module (SIM), for using the communication service of the corresponding service provider. The SIM is mounted within the terminal. In order for a mobile communication terminal user to use base stations of a plurality of service providers, the mobile communication terminal must be provided with subscriber information modules of all the respective service providers.
In the case of using a communication service, a mobile communication terminal user may habitually use only a specified subscriber information module (SIM), and in this case, the mobile communication terminal user cannot properly use services provided by the other service providers. Such services may include a call discount service between users belonging to the same communications company, a discount service within a network, and the like.